Dielectric resonator, dielectric resonator frequency adjusting method, and dielectric resonator integrated circuit

ABSTRACT

An oscillator comprising a dielectric resonator (DR) has a high controllability and reproducibility of coupling between the dielectric resonator (DR) and an oscillation circuit, and an integrated circuit is reduced in size. The dielectric resonator (DR) ( 1 ) is composed of a dielectric substrate ( 2 ), grounding conductive layers ( 3   a,    3   b ) formed on both sides of the dielectric substrate ( 2 ), and via holes ( 4   a ) for electrical connection between the conductive layers. A coupling element ( 7   a ) composed of a slot ( 5   a ) provided in the central portion of the grounding conductive layer ( 3   a ) and a patch ( 6   a ) surrounded by the slot ( 5   a ) is coupled to the dielectric resonator (DR) ( 1 ). The patch ( 6   a ) is connected to a transmission line ( 13   a ) on an oscillation circuit ( 9 ) through a bump ( 8 ). The transmission line ( 13   a ) is connected to the ground through a termination resistor ( 15   a ). On the oscillation circuit MMIC ( 9 ), the transmission line ( 13   a ) is connected to the gate of a transistor FET ( 14 ) A capacitive transmission line ( 13   a ) for positive feedback is connected to the transistor FET ( 14 ). The output of the transistor FET ( 14 ) is connected to a transmission line ( 13   c ) for output through a matching circuit ( 16 ). The transmission line ( 13   c ) is bump-connected to a coplanar line ( 12   a ) composed of a signal conductive layer ( 11   a ) formed on an edge of the dielectric resonator (DR) ( 1 ) and the grounding conductive layer ( 3   a ).

FIELD OF THE INVENTION

The present invention relates to a dielectric resonator which is used ina microwave band and in a millimeter wave band, a frequency adjustmentmethod for the waves of the bands, and an integrated circuit using thedielectric resonator.

BACKGROUND OF THE INVENTION

All of patents, patent applications, patent publications, scientificarticles and the like, which will hereinafter be cited or identified inthe present application, will hereby be incorporated by references intheir entirety in order to describe more fully the state of the art, towhich the present invention pertains.

A dielectric resonator (DR) is used in an oscillator used in a microwaveband and in a millimeter wave band for increasing stabilities for aphase noise and the frequency. FIG. 1 is an equivalent circuit showing aconfiguration of the oscillator using the dielectric resonator (DRO)according to one conventional example. For obtaining a negativeresistance, a capacitive micro strip line 28 b is connected to a sourceof transistor PET 14. A micro strip line 28 a extending from a gate oftransistor FET 14 is inductively coupled with a dielectric resonator 1having TE01d mode of cylindrical shape. In this configuration, acoupling rate is adjusted by a distance between dielectric resonator 1and micro strip line 28 a. Electromagnetic waves from transistor FET 14are reflected at a resonant frequency of dielectric resonator 1, andabsorbed with termination resistor 15 a at a frequency other then theresonant frequency. Therefore, there exists a large negative resistanceat the resonant frequency. Matching circuit 16 (which comprises atransmission line and a capacitor) being designed to comply anoscillation condition is connected to a drain of transistor FET 14. Gatebias 17 a and drain bias 17 b of transistor FET 14 are applied throughresistor 15 b of several kO and matching circuit 16, respectively. Inaddition, a resonant frequency is finely tuned by varactor diode 20connected to one terminal of micro strip line 28 c which is inductivelycoupled with dielectric resonator 1. Capacitor 21 a having a lowreactance at an operating frequency is connected to one side of varactordiode 20, add resistor 15 c having several kO which is DC grounded isconnected to the other side. In this configuration, because the resonantfrequency of dielectric resonator 1 is determined by an outsidedimension of the resonator, a high machining accuracy is required forthe resonator. Also, since the coupling rate is tuned by the distancebetween dielectric resonator 1 and micro strip line 28 a, a highpositioning accuracy (0.1 mm) of dielectric resonator 1 is required. Inaddition, as a electromagnetic field is spread out of the resonator, theoscillation frequency is easily changed when the resonator is mounted ona package.

Then, as a bonding structure of a dielectric resonator and atransmission line, a structure shown in FIG. 2 has been proposed inJapanese Laid-open Patent Publication No. 11-145709. FIG. 2 is anexploded perspective view showing a bonding structure of a dielectricresonator and a transmission line according to another conventionalexample. Dielectric resonator 1 comprises dielectric substrate 30 andconductive plates 29 a, 29 b. Conductor layers 31 a, 31 b havingcircular apertural parts facing to each other are formed on both uppersurface and bottom surface of dielectric substrate 30. Dielectric layer32 is formed on conductive layer 31 a using a thin film formationtechnology. In addition, signal conductive layer 33 is formed ondielectric layer 32. In this configuration, the apertural part ofdielectric substrate 30 operates as a resonator. In the JapaneseLaid-open Patent Publication No. 11-145709, as with the configuration inFIG. 1, the coupling rate is tuned by a distance between the resonatorand signal conductive layer 33. However, because a position of signalconductive layer 33 can be controlled accurately using a thin filmformation technology, a variation of the coupling rate is small.

On the other hand, in the example of the Japanese Laid-open PatentPublication No. 11-145709, even though spread of the electromagneticfiled out of the resonator is small compared with a dielectric resonatorwhich has a cylindrical shape, the electromagnetic filed also spreadsout upward and bottomward. Therefore, it has been necessary that, forexample, lines and a transistor FET other than a resonator, whichcompose the oscillator, have to be arranged keeping some distance fromthe resonator. That is, the lines and the transistor FET can not bedisposed in upward and bottomward of the resonator, thereby resulting inlarge size of the circuit. In addition, for the purpose of electricalshielding, conductive plates 29 a, 29 b covering a resonator portion areseparately needed as shown in FIG. 2.

DISCLOSURE OF THE INVENTION

It is therefore an object of the present invention to provide adielectric resonator which is free from the above issues.

It is another object of the present invention to provide an integratedcircuit having a dielectric resonator which is free from the aboveissues.

According to a first aspect of the present invention, the presentinvention provides a dielectric resonator which has an effectiveresonant area extending in three dimensions confining electromagneticwaves, wherein the dielectric resonator comprising at least one couplingelement, the at least one coupling element further comprising: at leastone slot formed on at least one conductive surface extending in twodimensions on at least a part of peripheral surface of the effectiveresonant area; and at least one patch conductive area adjacent to the atleast one slot.

It is favorable that an inside of the effective resonant area iscomposed of a dielectric substance, on the other hand, a periphery ofthe effective resonant area is composed of a conductive structureextending in two dimensions not to form a space beyond ½ of a wavelength of the electromagnetic waves at a resonant frequency, and the atleast one conductive surface forms a part of the conductive structure.

Also, it is favorable that the conductive structure extending to theperiphery of the effective resonant area comprises a first conductivelayer extending on a first surface of a dielectric substrate, a secondconductive layer extending on a second surface of the dielectricsubstrate, and at least one buried conductor buried in the dielectricsubstrate.

Further, it is favorable that the at least one buried conductorcomprises a plurality of buried conductors extending circularly anddiscontinuously if it is seen on a surface of the dielectric substrate,and a distance between the plurality of buried conductors is equal to orless than ½ of the wave length at the resonant frequency.

Furthermore, it is favorable that the plurality of buried conductors isa plurality of via plugs formed in a plurality of via holes passingthrough the dielectric substrate for connecting the first conductivelayer and the second conductive layer, and a distance between theplurality of via plugs is equal to or less than ½ of the wave length atthe resonant frequency.

The at least one buried conductor may be configured with buriedconductors extending circularly and discontinuously if it is seen on asurface of the dielectric substrate

The at least one slot may be formed on at least any one of the firstconductive layer and the second conductive layer.

The at least one conductive surface comprises the first conductivelayer, and at least one apertural part may be formed on an area of thesecond conductive layer corresponding to an area of the first conductivelayer where the at least one coupling element exists if the areas areseen on the surfaces of the dielectric substrate. The at least oneapertural part may be consist of a plurality of apertural parts withdifferent sizes. In addition, the plurality of apertural parts may bearranged in a concentric fashion. The at least one apertural part may befilled with a conductive material.

The slot may be formed to surround at least a part, of the patchconductive area. The slot may be formed to entirely surround the patchconductive area.

The at least one coupling element may be consist of a plurality ofcoupling elements. The plurality of coupling elements may be consist ofa plurality of same kinds of coupling element. The plurality of couplingelements may be consist of a plurality of different kinds of couplingelement.

The dielectric resonator may further comprise at least one coplanar lineformed on an area other than the effective resonant area.

The dielectric resonator may further comprise at least one coplanar lineformed in the effective resonant area.

The dielectric resonator may further comprise at least one coplanar lineformed in an area where the coupling element is formed.

The dielectric resonator may further comprise at least one signalconductive layer formed in an area where the coupling element exists soas to be adjacent to the at least one slot, and the at least one signalconductive layer may configure at least one coplanar line.

The at least one signal conductive layer may further be adjacent to theat least one patch conductive area. The at least one signal conductivelayer may further overlap with at least a part of the at least one patchconductive area.

The at least one coupling element may be connected to a negativeresistance generating circuit through at least one conductive contact.The conductive contact may be a conductive bump.

According to a second aspect of the present invention, the presentinvention provides an integrated circuit comprising: a dielectricresonator which has an effective resonant area extending in threedimensions confining electromagnetic waves, wherein the dielectricresonator comprises at least one coupling element, the at least onecoupling element comprising at least one slot formed on at least oneconductive surface extending in two dimensions on at least a part ofperipheral surface of the effective resonant area and at least one patchconductive area adjacent to the at least one slot; and at least onenegative resistance generating circuit connected to the at least onecoupling element through at least one conductive contact.

The conductive contact may be consist of a conductive bump.

It may be configured so that the at least one negative resistancegenerating circuit is formed on a first circuit substrate and includes afirst transmission line directly contacting to the at least oneconductive contact.

It may be configured so that the at least one negative resistancegenerating circuit further includes a varactor diode formed on the firstcircuit substrate, and the at least coupling element comprises a firstcoupling element connected to the first transmission line through afirst conductive contact and a second coupling element connected to thevaractor diode through a second conductive contact.

The at least one negative resistance generating circuit may configure anactive device including at least one oscillation circuit. It may beconfigured so that the at least one conductive contact is bonded to acenter part of the first transmission line, a first edge of the firsttransmission line is connected to the active device, and a second edgeof the first transmission line is connected to a termination resistor.Also, it may be configured so that the at least one coupling elementcomprises a first coupling element connected to an output side of theactive device through a first conductive contact and the firsttransmission line, and a second coupling element connected to atermination resistor through a second conductive contact and the firsttransmission line. Further, it may be configured so that the at leastone coupling element comprises a first coupling element connected to anoutput side of the active device through a first conductive contact andthe first transmission line, and a second coupling element connected toan output side of the active device through a second transmission line.

The first transmission line and a third transmission line formed on thefirst circuit substrate may be connected through a conductive bump.

The first transmission line and a fourth transmission line formed on asecond circuit substrate may be connected through a conductive bump.

It may be configured so that a concave portion is formed on the secondcircuit substrate, and the first circuit substrate mounted on thedielectric resonator is put in the concave portion. It may be configuredso that the first circuit substrate is encapsulated in the concaveportion of the second circuit substrate with a resin sealing a spacebetween the second circuit substrate and the dielectric resonator.

It may be configured so that an inside of the effective resonant area iscomposed of a dielectric substance, on the other hand, a periphery ofthe effective resonant area is composed of a conductive structureextending in two dimensions not to form a space beyond ½ of a wavelength of the electromagnetic waves at a resonant frequency, and the atleast one conductive surface forms a part of the conductive structure.

It may be configured so that the conductive structure extending to theperiphery of the effective resonant area, comprising: a first conductivelayer extending to a first surface of a dielectric substrate; a secondconductive layer extending to a second surface of the dielectricsubstrate; and at least one buried conductor buried in the dielectricsubstrate.

It may be configured so that the at least one buried conductor comprisesa plurality of buried conductors extending circularly anddiscontinuously if it is seen on a surface of the dielectric substrate,and a distance between the plurality of buried conductors is equal to orless than ½ of the wave length at the resonant frequency.

It may be configured so that the plurality of buried conductors is aplurality of via plugs formed in a plurality of via holes passingthrough the dielectric substrate for connecting the first conductivelayer and the second conductive layer, and a distance between theplurality of via plugs is equal to or less than ½ of the wave length atthe resonant frequency.

According to a third aspect of the present invention, the presentinvention provides a dielectric resonator comprising: a dielectricsubstrate; a first conductive layer formed on a first surface of thedielectric substrate; a second conductive layer formed on a secondsurface of the dielectric substrate; a plurality of via plugs filling aplurality of via holes arranged circularly and discontinuously if itseen on a surface of the dielectric substrate as well as passing throughthe dielectric substrate at intervals of equal to or less than ½ of awave length of the electromagnetic waves at a resonant frequency; aneffective resonant area extending in three dimensions and defined by thefirst and the second conductive layers and the plurality of buriedconductors for confining the electromagnetic waves; and at least onecoupling element formed on the first conductive layer in the effectiveresonant area, wherein the at least one coupling element includes atleast one slot formed on the first conductive layer and at least onepatch conductive area adjacent to the at least one slot.

It may be configured so that the at least one conductive surfacecomprises the first conductive layer, and at least one apertural part isformed on an area of the second conductive layer corresponding to anarea of the first conductive layer where the at least one couplingelement exists if the areas are seen on the surfaces of the dielectricsubstrate. The at least one apertural part may be consist of a pluralityof apertural parts with different sizes. The plurality of aperturalparts may be arranged in a concentric fashion. The at least oneapertural part may be filled with a conductive material.

The at least one coupling element may be consist of a plurality of samekinds of coupling element.

The at least one coupling element may be consist of a plurality ofdifferent kinds of coupling element.

It may be configured so that a dielectric resonator further comprises atleast one coplanar line formed at outside of the effective resonantarea.

It may be configured so that a dielectric resonator further comprises atleast one coplanar line formed in the effective resonant area.

It may be configured so that a dielectric resonator further comprises atleast one coplanar line formed in an area where the coupling element isformed.

It may be configured so that a dielectric resonator further comprises atleast one signal conductive layer formed in an area where the couplingelement exists so as to be adjacent to the at least one slot, and the atleast one signal conductive layer configures at least one coplanar line.It may be configured so that the at least one signal conductive layer isfurther adjacent to the at least one patch conductive area. Also, it maybe configured so that the at least one signal conductive layer partiallyoverlaps with at least a part of the at least one patch conductive area.

It may be configured so that the at least one coupling element isconnected to a negative resistance generation circuit through at leastone conductive contact. The conductive contact may be consist of aconductive bump.

According to a fourth aspect of the present invention, the inventionprovides an integrated circuit comprising: a dielectric substrate; afirst conductive layer formed on a first surface of the dielectricsubstrate; a second conductive layer formed on a second surface of thedielectric substrate; a plurality of via plugs filling a plurality ofvia holes arranged circularly and discontinuously if it seen on asurface of the dielectric substrate as well as passing through thedielectric substrate at intervals of equal to or less than ½ of a wavelength of the electromagnetic waves at a resonant frequency; aneffective resonant area extending in three dimensions and defined by thefirst and the second conductive layers and the plurality of buriedconductors for confining the electromagnetic waves; and at least onecoupling element formed on the first conductive layer in the effectiveresonant area, wherein the at least one coupling element comprising: adielectric resonator including at least one slot formed on the firstconductive layer and at least one patch conductive area adjacent to theat least one slot; and an oscillation circuit including a firsttransmission line connected to the at least one coupling element with aconductive bump as well as formed on a first circuit substrate.

It may be configured so that the oscillation circuit further comprises avaractor diode formed on the first circuit substrate, and the at leastone coupling element comprises a first coupling element connected to thefirst transmission line through a first conductive bump and a secondcoupling element connected to the varactor diode though a secondconductive bump. It may be configured so that a first edge of the firsttransmission line is connected to the oscillation circuit, and a secondedge of the first transmission line is connected to a terminationresistor.

Also, it may be configured so that the at least one coupling elementcomprises a first coupling element connected to an output side of theoscillation circuit through a first conductive bump and the firsttransmission line, and a second coupling element connected to atermination resistor through a second conductive bump and the firsttransmission line.

Further, it may be configured so that the at least one coupling elementcomprises a first coupling element connected to an output side of theoscillation circuit through a first conductive bump and the firsttransmission line, and a second coupling element connected to an outputside of the oscillation circuit through a second transmission line. Itmay be configured so that the first transmission line and a thirdtransmission line formed on the first circuit substrate are connectedthrough a conductive bump.

It may be configured so that the fast transmission line and a fourthtransmission line formed on a second circuit substrate are connectedthrough a conductive bump.

It may be configured so that a concave portion is formed on the secondcircuit substrate, and the first circuit substrate mounted on thedielectric resonator is put in the concave portion. It may be configuredso that the first circuit substrate is encapsulated in the concaveportion of the second circuit substrate with a resin sealing a spacebetween the second circuit substrate and the dielectric resonator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an equivalent circuit showing a configuration of an oscillatorusing a dielectric resonator (DRO) according to one conventionalexample.

FIG. 2 is an exploded perspective view showing a bonding structurebetween a dielectric resonator and a transmission line according to aconventional example.

FIG. 3A is a perspective view showing a dielectric resonator in a firstconfiguration example of a first embodiment of the present invention.

FIG. 3B is a traverse cross sectional view at A-A′ dashed line in FIG.3A showing an oscillator (DRO) having a dielectric resonator.

FIG. 3C is an equivalent circuit of an oscillator (DRO) having adielectric resonator shown in FIG. 3A.

FIG. 4A is a plane view showing a resonator part in a secondconfiguration example of a first embodiment of the present invention.

FIG. 4B is an equivalent circuit of an oscillator (DRO) having adielectric resonator shown in FIG. 4A.

FIG. 5 is a plane view showing a resonator part of a third configurationexample of a first embodiment.

FIG. 6A is a plane view showing a dielectric resonator of a firstconfiguration example in a second embodiment according to the presentinvention.

FIG. 6B is an equivalent circuit of an oscillator (DRO) having adielectric resonator shown in FIG. 6A.

FIG. 7A is a plane view showing a dielectric resonator of a firstconfiguration example of a third embodiment according to the presentinvention.

FIG. 7B is an equivalent circuit of an oscillator (DRO) having adielectric resonator shown in FIG. 7A.

FIG. 8 is a plane view showing a dielectric resonator of a secondconfiguration example of a third embodiment according to the presentinvention.

FIG. 9 is a traverse cross sectional view showing an oscillator (DRO)having a dielectric resonator of a first configuration example of afourth embodiment according to the present invention.

FIG. 10 is a traverse cross sectional view showing an oscillator (DRO)having a dielectric resonator of ti second configuration example of afourth embodiment according to the present invention.

FIG. 11A is a perspective view showing a dielectric resonator of a firstconfiguration example of a fifth embodiment according to the presentinvention.

FIG. 11B is a traverse cross sectional view at dashed line B-B′ of FIG.11A showing an oscillator (DRO) having a dielectric resonator mountedwith a flip chip bonding.

FIG. 12A is a figure showing calculation results of a resonant frequencychange vs the number of apertures formed on a dielectric resonatoraccording to the present invention.

FIG. 12B is a figure showing calculation results of a change of unload Qvs the number of apertures formed on a dielectric resonator according tothe present invention.

EMBODIMENTS OF THE PRESENT INVENTION

Embodiments of the present invention will be explained in detail byreferring to figures.

First Embodiment

FIG. 3A is a perspective view showing a dielectric resonator in a firstconfiguration example of a first embodiment of the present invention.FIG. 3B is a traverse cross sectional view at A-A′ dashed line in FIG.3A showing an oscillator (DRO) having a dielectric resonator. FIG. 3C isan equivalent circuit of an oscillator (DRO) having a dielectricresonator shown in FIG. 3A. Dielectric resonator 1 is configured suchthat ground conductive layers 3 a, 3 b are formed on both sides ofdielectric substrate 2, and the both conductive layers are connectedwith plug conductor 4 b filling circularly-arranged via hole 4 a. It isfavorable that a distance between via holes 4 a is less than ½, morefavorably less than ¼ of a wave length in the dielectric substrate forsuppressing leakage of the wave from a clearance between the via holes.A region surrounded by the via holes and ground conductive layers 3 a, 3b is named an effective resonant region. In this configuration,dielectric resonator 1 is a TE110 mode resonator at base operation.Coupling element 7 a consisting of slot 5 a at a center part of groundconductive layer 3 a and patch 6 a surrounded by slot 5 a is inductivelycoupled with dielectric resonator 1. A coupling rate is tuned by a widthof slot 5 a, a size of patch 6 a, and a position of patch 6 a. Sincecoupling element 7 a is fabricated using, for example, aphotolithography, a controllability of the coupling rate is high. Inthis embodiment, electromagnetic waves are confined almost in theeffective resonant area of dielectric substrate 2. Accordingly, as shownin FIG. 3B, oscillator circuit 9 can be mounted on the resonator with aflip chip bonding without effecting on a performance of the resonator,thereby resulting in achieving miniaturization.

Next, an oscillator (DRO) having a dielectric resonator of the presentembodiment will be explained. Patch 6 a and transmission line 13 a onoscillator circuit 9 are bonded through bump 8. Practically, a flip chipbonding is implemented. Transmission line 13 a is grounded throughtermination resistor 15 a. Then, only a resonant frequency is reflected,and the electromagnetic waves other than the resonant frequency areabsorbed with termination resistor 15 a. In oscillation circuit MMIC 9,transmission line 13 a is connected to a gate of transistor FET 14,which is an active device. For obtaining a negative resistance,capacitive transmission line 13 b for positive feedback is connected totransistor FET 14. A drain of transistor FET 14 is connected to outputtransmission line 13 c through matching circuit 16 consisting of atransmission line and a capacitor. Gate bias 17 a and drain bias 17 b oftransistor FET 14 are applied through resistor 15 b of several kO andmatching circuit 16, respectively. Output transmission line 13 c ofoscillation circuit 9 is bonded with a bump to coplanar line 12 aconsisting of signal conductive layer 11 a formed at the end of thesubstrate of dielectric resonator 1 and ground conductive layer 3 aarranged to sandwich slot 10 a. With this configuration, a signal of anoscillator (DRO) is transmitted from coplanar line 12 a. Thus, in theconfiguration of the present embodiment, output coplanar line 12 a isdisposed at outside of the effective resonant area, where is surroundedby through hole columns 4 a, of the dielectric substrate. Then, anapertural area is located only in coupling element 7 a on the resonator.As a result, a lowering of Q of the resonator due to fluctuation of theelectromagnetic field at the apertural area can be minimized.

FIG. 4A is a plane view showing a resonator part in a secondconfiguration example of the first embodiment of the present invention.FIG. 4B is an equivalent circuit of an oscillator (DRO) having adielectric resonator shown in FIG. 4A. A coupling element may be, asshown in FIG. 4A, coupling element 7 b connected two coplanar lines 19,which comprises ground conductive layer 3 a arranged to sandwich slot 5b with signal conductive layer 18 a, to patch 6 b. In this case, asshown in FIG. 4B, coupling element 7 b is connected in series totransmission line 13 a which is connected to a gate of transistor PET14. Therefore, a large coupling rate is easily obtained compared withthe case (coupling element 7 a) in which a coupling element is connectedin shunt to the gate through a bump having an inductance component. Inaddition, since coplanar line 19 is connected to coupling element 7 b,on-wafer evaluation can be easily conducted before mounting oscillationcircuit MMIC 9 on dielectric resonator 1.

FIG. 5 is a plane view showing a resonator part of a third configurationexample of the first embodiment. The coupling element may be, as shownin FIG. 5, coupling element 7 c configured by disposing patch 6 c byforming slot 5 c in ground conductive layer 3 a. In patch 6 c, signalconductive layer 18 b composing a coplanar line together with groundconductive layer 3 a may be connected. In the case of coupling element 7c, since the reflection occur in all frequencies, it is necessary not togenerate oscillation at an unnecessary frequency, while terminationresistor 15 a is not needed.

A TE110 mode resonator has been shown this time, however, the presentinvention is applicable to a resonator having a higher mode of, forexample, TE210 mode.

Second Embodiment

FIG. 6A is a plane view showing a dielectric resonator of a firstconfiguration example in a second embodiment according to the presentinvention. FIG. 6B is an equivalent circuit of an oscillator (DRO)having the dielectric resonator shown in FIG. 6A. As the secondembodiment, a configuration capable of electrically tuning a frequencyof the oscillator (DRO) having the dielectric resonator will be shown.Two coupling elements 7 d, 7 e are formed on ground conductive layer 3a. Coupling element 7 d is connected to transmission line 13 a extendingfrom a gate of transistor PET 14, and coupling element 7 e is connectedto varactor diode 20 formed on oscillation circuit MMIC 9. For applyingcontrol voltage 17 c to varactor diode 20, coupling element 7 e is DCconnected to the ground through resistor 15 c having several ⁻kO. Inaddition, capacitor 21 a which has a low reactance at an operatingfrequency is connected to the opposite side of coupling element 7 e. Byvarying control voltage 17 c, a capacitance of varactor diode 20 call bevaried, thereby resulting in capability of tuning a resonant frequency(oscillation frequency) of the resonator. It is possible to put atransmission line between coupling element 7 e and varactor diode 20. Inthe above, an example in which coupling element 7 e is employed as acoupling element with varactor diode 20 has been shown. However,coupling element 7 c may also be employed, In this case, there is anadvantage that resistor 15 c is not necessary because a voltage ofvaractor diode 20 at coupling element 7 c side is the ground voltage. Ofcourse, a configuration of coupling element 7 b instead of couplingelement 7 d may also be available.

Third Embodiment

FIG. 7A is a plane view showing a dielectric resonator of a firstconfiguration example of a third embodiment according to the presentinvention. FIG. 7B is an equivalent circuit of an oscillator (DRO)having the dielectric resonator shown in FIG. 7A. An output ofoscillation circuit 9 is connected to coupling element 7 f, which isconfigured by forming slot 5 d in ground conductive layer 3 a, throughcapacitor 21 b having a low reactance at an operating frequency whichcuts DC bias. In addition, coupling element 7 g is disposed in groundconductive layer 3 a by forming slot 5 e. Coupling element 7 g isconnected to coplanar line 12 b consisting of ground conductive layer 3a formed to sandwich slot 10 b with signal conductive layer 11 b bystepping over the inside and the outside of the resonator. In thisconfiguration, dielectric resonator 1 only outputs a resonant frequency,and reflects all waves other than the resonant frequency. In aconfiguration of this embodiment, a configuration of oscillation circuit9 forms a fundamental oscillator configuration, and a circuit designbecomes easy.

FIG. 8 is a plane view showing a dielectric resonator of a secondconfiguration example of the third embodiment according to the presentinvention. Coplanar line for output may be disposed two as shown in FIG.8. In this configuration, a signal inputted to dielectric resonator 1through coupling element 7 h is partially outputted to coplanar line 12c through coupling element 7 i, and the other of the signal is outputtedto coplanar line 12 d through coupling element 7 j. Thus, dielectricresonator 1 has a dividing function into two. Then, for example, in acase of heterodyne system, this can be used as a signal source of localoscillator for a transmitter and a receiver. In this case, a twodividing example has been shown, but not limited two. Dividing intothree or more is also available by increasing the number of couplingelements.

Fourth Embodiment

FIG. 9 is a traverse cross sectional view showing an oscillator (DRO)having a dielectric resonator of a first configuration example of afourth embodiment according to the present invention. Since theelectromagnetic waves are almost completely confined in dielectricresonator 1, it is expected that the oscillation frequency does notchange even if dielectric resonator 1, on which oscillator circuit 9 ismounted with a flip chip bonding, is further mounted on mountingsubstrate 22, such as a package, as shown in FIG. 9 by the flip chipbonding. Pit 23 is formed in mounting substrate 22, and oscillationcircuit 9 is set inside of pit 23. Ground conductive layer 3 d is formedon the backside surface of mounting substrate 22, and ground conductivelayer 3 c is formed on the surface of mounting substrate 22 except anarea of signal conductive layer 24. Coplanar line 12 a on dielectricresonator 1 is connected to a coplanar line consisting of signalconductive layer 24 on mounting substrate 22 and ground conductive layer3 c with bump 8. Ground conductive layers 3 c and 3 d are connected toeach other through plug conductor 4 d buried in via hole 4 c, which isarranged along a periphery of pit 23. With the above configuration, anarea in pit 23 where oscillation circuit 9 is set is electromagneticallyshielded.

FIG. 10 is a traverse cross sectional view showing an oscillator (DRO)having a dielectric resonator of a second configuration example of thefourth embodiment according to the present invention. As shown in FIG.10, an outer part of dielectric resonator 1 may be reinforced with, forexample, thermosetting resin 25. In the configuration of the presentinvention, since pit 23 is formed in mounting substrate 22, resin 25 isnot likely to get into an area of oscillation circuit MMIC 9, even ifresin 25 is coated on the outer periphery. Accordingly, it is expectedthat the oscillation characteristic does not change by using resin 25.

Fifth Embodiment

FIG. 11A is a perspective view showing a dielectric resonator of a firstconfiguration example of a fifth embodiment according to the presentinvention. FIG. 11B is a traverse cross sectional view at dashed lineB-B′ of FIG. 11A, showing an oscillator (DRO) having a dielectricresonator mounted with flip chip bonding. If dielectric resonator 1 ismounted on mounting substrate 22 with flip chip bonding, a back surfaceof dielectric resonator 1 faces to air. As shown in FIG. 11A, aplurality of apertures 26 are formed on ground conductive layer 3 b onthe backside of dielectric substrate 1. By filling apertures 26 with,for example, conductive paste 27 a or bonding wire 27 b, a resonantfrequency of dielectric resonator 1 can be tuned.

FIG. 12A is a figure showing calculation results of resonant frequencychange versus the number of apertures formed on a dielectric resonatoraccording to the present invention. Calculation results of resonantfrequency change when the number of apertures is varied are shown for aresonator at 38 GHz band. It can be seen that the resonant frequency canbe tuned in step like by varying the number of apertures 26. If theapertures are arranged in a concentric fashion against a center of theresonator, the tuning becomes easy because a tuning rate for theresonant frequency per one aperture of the concentric apertures becomesalmost equal. In addition, by varying a size of the aperture, the tuningrate of each aperture for the resonant frequency can be changed. If aplurality of sizes of the aperture is prepared, a fine tuning of theresonant frequency can be achieved by the different tuning rate of eachaperture.

FIG. 12B is a figure showing calculation results of a change of unload Qversus the number of apertures formed on a dielectric resonatoraccording to the present invention. The calculation results of unload Qfor the case of FIG. 12A are shown in FIG. 12B, however, no degradationis seen in the figure. In this case, an example, in which apertures 26are formed in advance and the apertures are filled one by one, has beenshown. However, it may also be possible to tune the resonant frequencyby sequentially forming aperture 26 one by one using, for example, alaser.

In the above, the preferred embodiments have been explained. However,the present invention is not limited to these embodiments and the eachembodiment may be changed within a technological scope and sprit of thepresent invention. In the embodiments, an example using a field effecttransistor as an active device has been shown. However, for example, abipolar transistor is also usable. Also, for connecting groundconductive layers 3 a and 3 b, and 3 c and 3 d on both surfaces of thesubstrate, it is possible to use a structure in which a conductive layeris formed only on an inner surface of a via hole such as a platedthrough hole instead of plug conductors 4 b, 4 d.

According to the present invention, by bonding an oscillation circuitwith flip chip bonding to a coupling element configured by forming aslot in a ground conductive layer on a dielectric resonator,controllability and reproducibility of the coupling rate of theoscillator using the dielectric resonator can be improved, and thecircuitry can also be minimized. In addition, according to theembodiment disposing a plurality of apertures with different sizes inthe ground conductive layer on the opposite side of the couplingelement, a fine tuning of the frequency can be achieved by controllingthe number of apertures.

In the present invention, a dielectric resonator is connected to anoscillation circuit as an example of a negative resistance generatingcircuit. However, if a circuit, as well as the oscillation circuit,generates a negative resistance, the effect of the present invention canbe extracted by connecting a dielectric resonator according to thepresent invention to the circuit. A bump is exemplified as a bondingmeans between the negative resistance generating circuit and thedielectric resonator, but not limited to the bump. Any conductivecontact is available even though a wiring which has a long distance isnot desirable.

POSSIBILITY FOR INDUSTRIAL APPLICATION

The present invention is applicable to anything if it is related to adielectric resonator used for a micro wave band and a millimeter waveband, to a frequency tuning method of the band, and to an integratedcircuit using the dielectric resonator. The application possibility isnot limited in its extension.

While the present invention has been described by associating with somepreferred embodiments and examples, it is to be understood that theseembodiments and examples are merely for illustrative of the invention byan example, and not restrictive. While it will be obvious to thoseskilled in the art that various changes and substitutions by equivalentcomponents and techniques are eased upon reading the specification, itis believed obvious that such changes and substitutions fit into thetrue scope and spirit

1-64. (canceled)
 65. A dielectric resonator which has an effectiveresonant area extending in three dimensions confining electromagneticwaves, wherein the dielectric resonator comprising at least one couplingelement, the at least coupling element, further comprising: at least oneslot formed on at least one conductive surface extending in twodimensions on at least a part of peripheral surface of the effectiveresonant area; and at least one patch conductive area adjacent to the atleast one slot, wherein an inside of the effective resonant area iscomposed of a dielectric substance, on the other hand, a periphery ofthe effective resonant area is composed of a conductive structureextending in two dimensions not to form a space beyond ½ of a wavelength of the electromagnetic waves at a resonant frequency, and the atleast one conductive surface forms a part of the conductive structure,wherein the conductive structure extending to the periphery of theeffective resonant area comprises a first conductive layer extending ona first surface of a dielectric substrate, a second conductive layerextending on a second surface of the dielectric substrate, and at leastone buried conductor buried in the dielectric substrate, wherein the atleast one conductive surface comprises the first conductive layer, andat least one apertural part is formed on an area of the secondconductive layer corresponding to an area of the first conductive layerwhere the at least one coupling element exists if the areas are seen onthe surfaces of the dielectric substrate.
 66. A dielectric resonatoraccording to claim 65, wherein the at least one apertural part comprisesa plurality of apertural parts with different sizes.
 67. A dielectricresonator according to claim 66, wherein the plurality of aperturalparts is arranged in a concentric fashion.
 68. A dielectric resonatoraccording to claim 65, wherein the at least one apertural part is filledwith a conductive material.
 69. An integrated circuit, comprising: adielectric resonator which has an effective resonant area extending inthree dimensions confining electromagnetic waves, wherein the dielectricresonator comprising at least one coupling element, the at leastcoupling element further comprising at least one slot formed on at leastone conductive surface extending in two dimensions on at least a part ofperipheral surface of the effective resonant area, and at least onepatch conductive area adjacent to the at least one slot; and at leastone negative resistance generating circuit connected to the at least onecoupling element through at least one conductive contact.
 70. Anintegrated circuit according to claim 69, wherein the conductive contactcomprises a conductive bump.
 71. An integrated circuit according toclaim 69, wherein the at least one negative resistance generatingcircuit is formed on a first circuit substrate, and includes a firsttransmission line directly contacting to the at least one conductivecontact.
 72. An integrated circuit according to claim 71, wherein the atleast one negative resistance generating circuit further includes avaractor diode formed on the first circuit substrate, and the at leastone coupling element comprises a first coupling element connected to thefirst transmission line through a first conductive contact and a secondcoupling element connected to the varactor diode through a secondconductive contact.
 73. An integrated circuit according to claim 71,wherein the at least one negative resistance generating circuit includesat least one active device, the at least one conductive contact isconnected to a center part of the first transmission line, and a firstedge of the first transmission line is connected to the active deviceand a second edge of the first transmission line is connected to atermination resistor.
 74. An integrated circuit according to claim 71,wherein the at least one negative resistance generating circuit includesat least one active device, and the at least one coupling element isconnected to a termination resistor through a second conductive contactand the first transmission line, as well as connected to the activedevice through a first conductive contact and the first transmissionline.
 75. An integrated circuit according to claim 71, wherein the atleast one negative resistance generating circuit includes at least oneactive device, and the at least one coupling element comprises a firstcoupling element connected to an output side of the active devicethrough a first conductive contact and a second transmission line formedon the first circuit substrate, and a second coupling element connectedto a transmission line formed at outside of the effective resonant area.76. An integrated circuit according to claim 71, wherein a transmissionline formed at outside of the effective resonant area and a thirdtransmission line formed on the first circuit substrate are connectedthrough a conductive bump.
 77. An integrated circuit according to claim71, wherein a transmission line formed at outside of the effectiveresonant area and a fourth transmission line formed on a second circuitsubstrate are connected through a conductive bump.
 78. An integratedcircuit according to claim 77, wherein a concave portion is formed onthe second circuit substrate, and the first circuit substrate mounted onthe dielectric resonator is put in the concave portion.
 79. Anintegrated circuit according to claim 78, wherein the first circuitsubstrate is encapsulated in the concave portion of the second circuitsubstrate with a resin sealing a space between the second circuitsubstrate and the dielectric resonator.
 80. An integrated circuitaccording to claim 69, wherein an inside of the effective resonant areais composed of a dielectric substance, on the other hand, a periphery ofthe effective resonant area is composed of a conductive structureextending in two dimensions not to form a space beyond ½ of a wavelength of electromagnetic waves at a resonant frequency, and the atleast one conductive surface forms a part of the conductive structure,wherein the conductive structure extending to the periphery of theeffective resonant area comprises a first conductive layer extending ona first surface of a dielectric substrate, a second conductive layerextending on a second surface of the dielectric substrate, and at leastone buried conductor buried in the dielectric substrate, wherein the atleast one buried conductor comprises a plurality of buried conductorsextending circularly and discontinuously if it is seen on a surface ofthe dielectric substrate, and a distance between the plurality of buriedconductors is equal to or less than ½ of the wave length at the resonantfrequency, wherein the plurality of buried conductors is a plurality ofvia plugs formed in a plurality of via holes passing through thedielectric substrate for connecting the first conductive layer and thesecond conductive layer, and a distance between the plurality of viaplugs is equal to or less than ½ of the wave length at the resonantfrequency.
 81. A dielectric resonator, comprising: a dielectricsubstrate; a first conductive layer formed on a first surface of thedielectric substrate; a second conductive layer formed on a secondsurface of the dielectric substrate; a plurality of via plugs filling aplurality of via holes arranged circularly and discontinuously if it isseen on a surface of the dielectric substrate as well as passing throughthe dielectric substrate at intervals of equal to or less than ½ of awave length of electromagnetic waves at a resonant frequency; aneffective resonant area extending in three dimensions and defined by thefirst and the second conductive layers and a plurality of buriedconductors for confining the electromagnetic waves; and at least onecoupling element formed on the first conductive layer in the effectiveresonant area, wherein the at least one coupling element includes atleast one slot formed on the first conductive layer and at least onepatch conductive area adjacent to the at least one slot.
 82. Adielectric resonator according to claim 81, wherein the at least oneconductive surface comprises the first conductive layer, and at leastone apertural part is formed on an area of the second conductive layercorresponding to an area of the first conductive layer where the atleast one coupling element exists if the areas are soon on the surfacesof the dielectric substrate.
 83. A dielectric resonator according toclaim 82, wherein the at least one apertural part comprises a pluralityof apertural parts with different sizes.
 84. A dielectric resonatoraccording to claim 83, wherein the plurality of apertural parts isarranged in a concentric fashion.
 85. A dielectric resonator accordingto claim 82, wherein the at least one apertural part is filled with aconductive material.
 86. A dielectric resonator according to claim 82,wherein the at least one coupling element comprises a plurality ofcoupling elements which includes two types of coupling element, the oneis a first coupling element in which the slot at least partiallysurrounds the patch conductive area, the other is a second couplingelement in which the slot entirely surrounds the patch conductive area.87. A dielectric resonator according to claim 82, further comprising atleast one coplanar line formed at outside of the effective resonantarea.
 88. A dielectric resonator according to claim 87, wherein the atleast one coplanar line further formed at inside of the effectiveresonant area shares a signal conductive layer with at least onecoplanar line formed at outside of the effective resonant area.
 89. Adielectric resonator according to claim 81, further comprising at leastone signal conductive layer formed in an area where the coupling elementexists so as to be adjacent to the at least one slot, and the at leastone signal conductive layer configures at least one coplanar line and atleast partially overlaps with a pap: of the at least one patchconductive area.
 90. A dielectric resonator according to claim 81,wherein the at least one coupling element is connected to a negativeresistance generation circuit through at least one conductive contact.91. A dielectric resonator according to claim 90, wherein the conductivecontact comprises a conductive bump.